|Publication number||US7066474 B2|
|Application number||US 10/387,418|
|Publication date||Jun 27, 2006|
|Filing date||Mar 14, 2003|
|Priority date||Mar 14, 2003|
|Also published as||CA2422864A1, CA2422864C, US20040178587|
|Publication number||10387418, 387418, US 7066474 B2, US 7066474B2, US-B2-7066474, US7066474 B2, US7066474B2|
|Inventors||Grant W. Hiebert, Jack W. Fenkhuber, Gerald W. Clancy|
|Original Assignee||Valid Manufacturing Ltd.|
|Export Citation||BiBTeX, EndNote, RefMan|
|Patent Citations (53), Referenced by (39), Classifications (28), Legal Events (3)|
|External Links: USPTO, USPTO Assignment, Espacenet|
This invention relates to the field of both vehicle suspension and level control systems.
Applicant is aware of U.S. Pat. No. 5,288,102 which issued Feb. 22, 1994 to Machida for a Vehicle Height Control System. Machida discloses a compact vehicle height control system capable of changing the spring constant of gas springs to thereby control the vehicle attitude stabilizing characteristics so as to provide a comfortable vehicle ride. Pilot-controlled directional control valves are interposed in passages that connect first and second gas springs in parallel. When the pilot-controlled directional control valves are opened, the first and second gas springs are communicated with respective cylinders in parallel, whereas, when the directional control valves are closed, only the first gas springs are communicated with the cylinders, thereby changing the spring constant. The pilot-controlled directional control valves are hydraulically operable, thereby eliminating solenoid operated valves.
In the present invention it is an object to provide that which is neither taught nor suggested by Machida, namely a suspension system which employs ride cushion air reservoirs in parallel to provide for a more plush, well cushioned suspension for a coach while driving which is adapted to address the problem with such a soft suspension where a motor coach will, for example, dive during cornering. Thus, it is desirable, and an object of the present invention to make the suspension more firm as the coach enters a corner or otherwise subject to accelerations not ordinarily encountered during straight and level or gentle curves in the road. This is accomplished in the present invention by the use of lock out or “anti-dive” valves which close off the parallel air reservoirs from the suspension air-springs. It is a further object to provide for ride levelling and levelling of the vehicle about three axes.
The present invention is an advanced vehicle suspension and level control system for installation on vehicle suspensions utilizing two or more air-springs such as employed for example in recreational vehicles (RV's). The system utilizes a distributed sensing and control approach, utilizing one or more intelligent sensor and input/output (I/O) module(s) along with a system controller such as a data processor. The system is designed to operate with two or more degrees of freedom or control axes dependent on the specific application and suspension type.
On a chassis with mechanical spring front suspension system, a two axis system controls the level of the rear axle in relation to the non-controllable front axle, along with the longitudinal axis. That is, the two degrees of freedom of this system are rotation about the venicle's longitudinal axis and rotation about a pitch axis which is horizontal perpendicular to the longitudinal axis, and coincides with the front axles as governed by the vertical length of the two rear air springs along their two vertical axes. On a chassis with a single control air-spring type front suspension, a three axis system controls the level of the rear axle in relation to the front, along with controlling the pitch of, and rotation of the chassis about, the longitudinal axis. The three control points are two rear air-springs and a single control dual air-spring on the front axle. That is, the height of the two rear corners and front of the vehicle are actively controlled along the two rear corner air-spring vertical axes as before, with the addition of the front axle raising or lowering along a vertical third axis notionally between the two front corners. On a chassis with a dual control air-spring type front suspension in which the front air-springs are controlled independently, a four axis control method (one vertical axis for each of the four corner air-springs) is utilized to provide a high degree of system capability. Other suspension systems may also be suitable for the application of this system.
One function of this system is to provide automated and manual leveling of a parked vehicle. The manual leveling is accomplished through the use of system control requests which are transmitted via a Controller Area Network (CAN) to an intelligent sensor and I/O module(s). The system controller provides a means for an operator to accomplish this task and to provide input and feedback. When an operator places the system in manual mode, the operator can control the raising and lowering of the air-springs, either independently or simultaneously.
The system incorporates ride cushion air reservoirs in tandem with the air-springs which provide for a plush, well cushioned suspension while the vehicle is in motion. Another function of the present invention provides for a more firm suspension when the vehicle is, for example during cornering, subject to excess transverse or longitudinal accelerations not ordinarily encountered during straight-and-level or gentle curves in the road. In particular, the present invention incorporates lock-out or anti-dive valves which close off the parallel ride-cushion air reservoirs.
The vehicle may be automatically leveled when it is not in motion. Automatic leveling is accomplished by initiating an automatic level request message via the CAN to the intelligent sensor and I/O module(s). When this automatic leveling mode is initiated, the system purges air from all air-springs, which lowers the vehicle as close as possible to the ground. The system maintains the air purge for the duration specified and programmed by the vehicle manufacturer. Once the vehicle lowering time has been reached, the system stops the purge process and analyzes the tilt angle of the accelerometer(s) to determine which point of the vehicle is the highest relative to the rest. This point is the leveling reference point to which the remaining axes are raised. The system then begins to level the vehicle by monitoring the tilt angle data from the accelerometer while raising the remaining control points to that of the leveling reference point, thereby achieving an effective tilt angle of zero. Once the system achieves the initial ‘zero’, the system performs three iterations of verifying the level and adjusting the control points by raising or lowering them, if necessary. If so programmed by the vehicle manufacturer, the system controller may prevent excessive chassis twist by limiting the range of motion of each of the air-springs. This is accomplished by measuring and comparing the relative tilt angles of the front and rear transverse accelerometers. If the relative tilt angle exceeds the programmable limit defined by the vehicle manufacturer, further control action which will induce additional twist may be restricted.
In one embodiment of the invention, the vehicle is equipped with one or two ride height sensors per axle which connect directly to the intelligent sensor and I/O module(s) and produce a duty cycle modulated digital signal which directly corresponds to the rotational position of the sensor input shaft. Typically, the ride height sensor is mounted to the chassis and the input shaft is connected to a lever that is attached to the axle or suspension component that moves in relation to the chassis. Each ride height sensor incorporates a microcontroller and a rotational magnetic field detector, resulting in non-contact measurement of the rotational position of the input shaft. The ride height sensors provide dynamic sensing of the position of the chassis relative to the suspension. The feedback from the sensors may be used to manually set or actively control the ride height of the vehicle, for example to lower the height of the vehicle above the road to reduce drag during cruising, or to raise the vehicle when in rough terrain.
In summary, the suspension and level control system for vehicles according to the present invention includes, so as to independently control inflation and deflation of left and right rear air-springs, corresponding left rear and right rear pneumatic circuits in fluid communication with a pressurized air source, wherein each air-spring has at least one air ride cushion reservoir mounted in a parallel pneumatic circuit in parallel fluid communication with the air-spring, and wherein each pneumatic circuit includes a selectively actuable valve means for: (a) selectively passing pressurized air from the air source into the corresponding parallel pneumatic circuit to selectively inflate the air-spring thereby raising a corresponding corner of the vehicle; and, (b) selectively venting pressurized air from the corresponding parallel pneumatic circuit to selectively deflate the air-spring, thereby lowering a corresponding corner of the vehicle.
The system further includes at least one accelerometer for sensing a pitch angle and/or a roll angle of the vehicle about corresponding respective lateral and/or longitudinal axes of the vehicle. Data corresponding to at least the pitch inclination and/or roll inclination of the vehicle, which may also for example include rates of pitch and/or roll when the vehicle is in translation above a low non-static threshold, is communicated by a communication means to a processor. The communication means may be a wiring harness or buss or other means for transmission of a control signal from a processor. The processor may then send a control signal to the valve means to actively correct at least the pitch inclination and/or the roll inclination to attempt to return the vehicle to level or to within a preset range of acceptable limits when leveling the vehicle. Control signals to the valve means also allows for ride height adjustment.
In the preferred embodiment, selectively actuable anti-dive valves are mounted into the parallel pneumatic circuit so as to control fluid communication between the corresponding air-spring and its air ride cushion reservoir or reservoirs. The processor communicates with the anti-dive valves to selectively isolate the reservoirs from the corresponding pneumatic circuit upon data from the at least one accelerometer indicating excessive pitch and/or roll rates, when compared to preset threshold values, which would cause diving of the vehicle during maneuvering due to the added resiliency in the pneumatic circuit of the reservoir.
The accelerometers indicate longitudinal and/or lateral accelerations of the chassis exceeding preset threshold acceleration values. The processor determines corresponding pitch and/or roll rates corresponding to the accelerations and compares the pitch and/or roll rates to preset threshold pitch and/or roll rate values to predict diving of the vehicle during manoeuvring.
The system may further include front left and front right air-springs mounted to the chassis, the front air-springs in fluid communication with the air source via a single front pneumatic circuit mounted to the chassis. The vehicle is thus selectively levelable upon selective independent inflation or deflation of the left rear air-spring or the right rear air-spring or the front air-springs parallel to a corresponding three axes. The three axes may be vertical axes, one in each rear corner and one in the front of the vehicle. The front pneumatic circuit may have an air ride cushion reservoir mounted in a parallel pneumatic circuit in parallel fluid communication therewith.
Alternatively, the system may include a front left air-spring mounted to the chassis in fluid communication with the air source via a front left pneumatic circuit mounted to the chassis, and a front right air-spring mounted to the chassis in fluid communication with the air source via a front right pneumatic circuit mounted to the chassis. The vehicle is thus selectively levelable upon selective independent inflation or deflation of the air-springs parallel to a corresponding four axes, where the four axes may be vertical axes, one in each front and rear corner of the vehicle. The left front and right front pneumatic circuits may each have an air ride cushion reservoir mounted in a parallel pneumatic circuit in parallel fluid communication therewith.
In use, as illustrated in
Lines 14 a and 18 a terminate downstream at selector valve 120 a. Lines 14 b and 18 b terminate downstream at selector valve 120 b. The biasing of selector valves 120 a and 120 b determines whether airflow from lines 14 a and 14 b respectively, or airflow from lines 18 a and 18 b respectively enter air-spring feed lines 24 a–24 d. Airflow in air-spring feed lines 24 a–24 d communicates with air-springs 116 a–116 d respectively via branch lines 26 a–26 d at junctions 28 a–28 d. Lines 30 a–30 d also branch from junctions 28 a–28 d respectively, and feed airflow to and from air cushion reservoirs 118 a–118 d respectively.
The biasing of valves 124 a, 124 b, 122 a, 122 b, and 120 a, 120 b is controlled by instructions from control module 110 via network bus 110 a and I/O module 112. For example, in travel mode, valve 120 a is biased to pass airflow between line 14 a and lines 24 a, 24 b so that valve 126 a regulates the airflow to air-springs 116 a, 116 b to adjust the ride height. During travel the shock absorbing resiliency of the air-springs is supplemented by air cushion reservoirs mounted in parallel, on lines 30 a, 30 b, with the air-springs. In modes permitting manual adjustment of the height of the RV above the ground (that is, adjusting the length or expansion of air-spring 116 a), or in automatic modes, for example for automatic levelling of the RV while the RV is static, valve 120 a is biased to pass airflow between line 18 a and lines 24 a, 24 b so that valves 122 a, 124 a regulates the airflow to (in the case of valve 124 a) and from (in the case of valve 122 a) air-springs 116 a, 116 b to adjust the height of the RV chassis in the corresponding corner, in this case the left rear. Opening valve 124 a raises the corner by expanding the air-springs. Opening valve 122 a lowers the corners by venting air from the air-springs.
As may be seen, the ride height valve 126 a and associated branch line 14 a, and the raise valve 124 a of the height control valves on branch line 18 a form a first kind of parallel pneumatic circuit between junction 12 and selector valve 120 a. Thus, the outputs from the I/O module 112 which control the biasing of selector valve 120 a will regulate which of the two parallel branches of the first kind of parallel pneumatic circuit will govern the downstream actuation of the air-springs 116 a, 116 b. The use of a parallel pneumatic circuit downstream from a pressurized air source which incorporates two branches, one of which provides for ride height control, and the other of which provides for static height control, the operative branch depending on the biasing of a selector valve common to the two branches, for downstream actuation of one or more air-springs, is the basic pneumatic circuit upon which the illustrated embodiments of
The use of the same kind of parallel pneumatic circuits are employed as the building blocks in the further embodiments of
Also what is added to the embodiments of
Thus during straight and level translation, that is travel, or during mild manoeuvring, the ride cushion reservoirs are left in open fluid communication with their corresponding air-springs, in
As will be apparent to those skilled in the art in the light of the foregoing disclosure, many alterations and modifications are possible in the practice of this invention without departing from the spirit or scope thereof. Accordingly, the scope of the invention is to be construed in accordance with the substance defined by the following claims.
|Cited Patent||Filing date||Publication date||Applicant||Title|
|US3573884||Jun 3, 1969||Apr 6, 1971||Knorr Bremse Gmbh||Air bellows suspension system for vehicles|
|US3921999||Jun 12, 1973||Nov 25, 1975||Lear Siegler Inc||Vehicle suspension construction and sub-assembly therefor|
|US3963261||Mar 3, 1975||Jun 15, 1976||Nissan Motor Co., Ltd.||Vehicle suspension system|
|US4238128||Sep 7, 1978||Dec 9, 1980||Grumman Flexible Corporation||Combination load-leveling and kneeling air suspension system|
|US4373744||Dec 31, 1980||Feb 15, 1983||Lucas Industries Limited||Suspension control system for a road vehicle|
|US4462610||Jun 17, 1982||Jul 31, 1984||Tokico Ltd.||Vehicle height adjusting apparatus|
|US4518169||Mar 18, 1983||May 21, 1985||Nissan Motor Company, Limited||Automatic vehicle height-adjusting system|
|US4580798||Nov 13, 1984||Apr 8, 1986||Roelofs Robert E||Air suspension system for the rear end of a motor home|
|US4613116||Nov 28, 1984||Sep 23, 1986||Toyota Jidosha Kabushiki Kaisha||Air suspension|
|US4614247||Oct 26, 1984||Sep 30, 1986||Airstream, Inc.||Composite multi-axle suspension for vehicles|
|US4634142||Aug 27, 1984||Jan 6, 1987||C & K Venture Income I-Coast||Computer optimized adaptive suspension system|
|US4696483||Jun 20, 1985||Sep 29, 1987||Mitsubishi Jidosha Kogyo K.K.||Vehicle suspension apparatus|
|US4696489||Jan 13, 1986||Sep 29, 1987||Nissan Motor Company, Limited||Automotive suspension system with variable damping characteristics|
|US4709934||Dec 18, 1985||Dec 1, 1987||Kabushiki Kaisha Showa Seisakusho||Vehicle leveling system|
|US4733876 *||Dec 17, 1986||Mar 29, 1988||Heider Merle J||Suspension and leveling system for a vehicle|
|US4787644||May 6, 1987||Nov 29, 1988||Nissan Motor Company, Limited||Height control system for automotive vehicle with vehicular profile regulating feature|
|US4852863||Jun 16, 1988||Aug 1, 1989||Robert Bosch Gmbh||Pneumatic suspension for motor vehicles|
|US4881753||Nov 29, 1988||Nov 21, 1989||Toyota Jidosha Kabushiki Kaisha||Air suspension system with an air drier|
|US4934731||Jun 8, 1989||Jun 19, 1990||Fuji Jukogyo Kabushiki Kaisha||Control device for an active fluid suspension system of motor vehicles|
|US5005858||Dec 21, 1989||Apr 9, 1991||Fiat Auto S.P.A.||Hydropneumatic vehicle suspension system of variable attitude|
|US5048867||May 29, 1990||Sep 17, 1991||Wabco Westinghouse Fahrzeugbremsen Gmbh||Automatic level control system for vehicles|
|US5127667||Nov 13, 1990||Jul 7, 1992||Matsushita Electric Industrial Co., Ltd.||Suspension control apparatus|
|US5130927||May 10, 1990||Jul 14, 1992||Toyota Jidosha Kabushiki Kaisha||Vehicle height control device adapted for self stopping in fault operation and restarting|
|US5222759||Jul 20, 1992||Jun 29, 1993||Robert Bosch Gmbh||Apparatus for active control of body motions in motor vehicles|
|US5273308||Nov 6, 1990||Dec 28, 1993||Rubery Owen-Rockwell Limited||Height control of air suspended vehicles|
|US5322321 *||Dec 28, 1992||Jun 21, 1994||Ford Motor Company||Vehicle active suspension system|
|US5344189||Feb 25, 1992||Sep 6, 1994||Isuzu Motors Limited||Vehicle height adjusting device|
|US5375873||Feb 28, 1994||Dec 27, 1994||Thackray; Donald S.||Automotive air suspension system|
|US5466007||Sep 14, 1992||Nov 14, 1995||Dunlop Limited||Vehicle suspension system|
|US5484162||Feb 1, 1994||Jan 16, 1996||Aisin Seiki Kabushiki Kaisha||Vehicle height control System|
|US5566971||Jul 27, 1995||Oct 22, 1996||Safari Motor Coaches, Inc.||Vehicle air suspension system|
|US5570287||Dec 16, 1994||Oct 29, 1996||Ford Motor Company||Speed dependent suspension control|
|US5601307||Oct 24, 1994||Feb 11, 1997||Kinetic Limited||Vehicle suspension system|
|US5765115||Aug 4, 1995||Jun 9, 1998||Ford Motor Company||Pneumatic tilt stabilization suspension system|
|US5864768||Sep 9, 1996||Jan 26, 1999||Ford Global Technologies, Inc.||Vehicle suspension control system|
|US5999868||Feb 26, 1997||Dec 7, 1999||Board Of Regents The University Of Texas System||Constant force suspension, near constant force suspension, and associated control algorithms|
|US6015155||May 27, 1997||Jan 18, 2000||Rover Group Limited||Motor vehicle suspension system|
|US6050573||Sep 30, 1998||Apr 18, 2000||Kwikee Products Co., Inc.||Automatic leveling system for vehicles|
|US6157879||Sep 5, 1997||Dec 5, 2000||Mando Corporation||Method for controlling suspension apparatus for vehicle|
|US6173974 *||Sep 28, 1999||Jan 16, 2001||Ford Global Technologies, Inc.||Detecting jacking or hoisting of a vehicle having a suspension system that includes gas levelers|
|US6189903||Nov 19, 1998||Feb 20, 2001||Btr Industries, Ltd.||Vehicle suspension gas supply system|
|US6203026||Sep 22, 1999||Mar 20, 2001||Marcus Jones||Air suspension override system|
|US6234493||May 11, 1999||May 22, 2001||Wabco Gmbh||Level control system|
|US6264213||Mar 24, 2000||Jul 24, 2001||Daimlerchrysler Ag||Suspension system for land vehicles, in particular motor vehicles|
|US6293562||Nov 18, 1999||Sep 25, 2001||Daimlerchrysler Ag||Method and apparatus for controlling ride height of a wheeled vehicle|
|US6332623||Aug 4, 1999||Dec 25, 2001||Continental Aktiengesellschaft||Level adjustment device for vehicles with air springs|
|US6338014||Jun 27, 1996||Jan 8, 2002||Kinetic Limited||Control method for vehicle suspension system|
|US6382370||Sep 1, 1999||May 7, 2002||K2 Bike, Inc.||Shock absorber with an adjustable lock-out value and two-stage flow restriction|
|US6394238||Dec 7, 2000||May 28, 2002||Husco International, Inc.||Regenerative suspension for an off-road vehicle|
|US6398236||Jul 11, 2000||Jun 4, 2002||Holland Neway International, Inc.||Lift axle suspension with axle reservoir|
|US6768936||Sep 5, 2003||Jul 27, 2004||Preston Product Design & Development||Automated control system for vehicle leveling and elimination of torsion in a vehicle chassis|
|US20010024021||Jan 25, 2001||Sep 27, 2001||Allen Walter Roy||Working apparatus|
|WO2000006400A1||Jul 29, 1999||Feb 10, 2000||Haire Angela Kate||Vehicle suspension with linked air bags|
|Citing Patent||Filing date||Publication date||Applicant||Title|
|US7221265 *||Sep 24, 2003||May 22, 2007||Kongsberg Automotive Asa||System for sensing level change in vehicles|
|US7226057 *||May 11, 2004||Jun 5, 2007||Days Corporation||Apparatus and method for automatically leveling an object|
|US7240911 *||May 19, 2004||Jul 10, 2007||Escalante Enterprises, L.L.C.||System for controlling distribution of fluid to a system of air bags for use with vehicular trailers|
|US7261304 *||Jan 27, 2004||Aug 28, 2007||Hadley Products||Vehicle leveling system|
|US7389994||Jun 21, 2007||Jun 24, 2008||Hadley Products||Vehicle leveling system|
|US7416190 *||Sep 1, 2005||Aug 26, 2008||Arlin Gene Sandbulte||Air suspension system for a vehicle|
|US7441782 *||Apr 28, 2004||Oct 28, 2008||Continental Aktiengesellschaft||Method for controlling the level of pneumatic level control systems in motor vehicles|
|US7530577 *||Jun 6, 2008||May 12, 2009||Arlin Gene Sandbulte||Air suspense system for a vehicle|
|US7607672 *||Nov 8, 2007||Oct 27, 2009||Aisin Seiki Kabushiki Kaisha||Vehicle height adjusting apparatus|
|US7617018 *||Oct 18, 2005||Nov 10, 2009||Innovative Design Solutions||Platform attitude adjustment augmentation method and apparatus|
|US7815200||Nov 15, 2007||Oct 19, 2010||Actuant Corporation||Medical imaging leveling|
|US7850195 *||Apr 5, 2007||Dec 14, 2010||Simard Suspensions Inc.||Tandem suspension for steerable axles|
|US8196723||Nov 13, 2009||Jun 12, 2012||Robust Systems Solutions, LLC||Pneumatic damper|
|US8306696||Oct 8, 2009||Nov 6, 2012||Driveright Holdings, Ltd.||Method and system for aligning a vehicle with an artificial horizon|
|US8520794 *||Jun 16, 2005||Aug 27, 2013||General Electric Company||Method and device for facilitating a uniform loading condition for a plurality of support members supporting a steam dryer in a nuclear reactor|
|US8712638 *||Aug 14, 2012||Apr 29, 2014||Dr. Ing. H.C.F. Porsche Aktiengesellschaft||Control unit of a ride level control system, and ride level control system|
|US9045015||Mar 7, 2014||Jun 2, 2015||Ford Global Technologies, Llc||Laterally tiltable, multitrack vehicle|
|US9090281||Mar 7, 2014||Jul 28, 2015||Ford Global Technologies, Llc||Laterally tiltable, multitrack vehicle|
|US9145168||Mar 7, 2014||Sep 29, 2015||Ford Global Technologies, Llc||Laterally tiltable, multitrack vehicle|
|US9248857||Mar 7, 2014||Feb 2, 2016||Ford Global Technologies, Llc||Laterally tiltable, multitrack vehicle|
|US20040256815 *||May 11, 2004||Dec 23, 2004||Eichhorn Mark M.||Apparatus and method for automatically leveling an object|
|US20040256831 *||Feb 21, 2002||Dec 23, 2004||Sharp Keith Leslie||Vehicle suspension|
|US20050161891 *||Jan 27, 2004||Jul 28, 2005||Trudeau Curtis A.||Vehicle leveling system|
|US20050271464 *||Sep 24, 2003||Dec 8, 2005||Sven Bjorkgard||System for sensing level change in vehicles|
|US20060088385 *||Oct 18, 2005||Apr 27, 2006||Innovative Design Solutions||Platform attitude adjustment augmentation method and apparatus|
|US20060285625 *||Jun 16, 2005||Dec 21, 2006||Erbes John G||Method and device for facilitating a uniform loading condition for a plurality of support members supporting a steam dryer in a nuclear reactor|
|US20070040344 *||Apr 28, 2004||Feb 22, 2007||Continental Aktiengesellschaft||Method for controlling the level of pneumatic level control systems in motor vehicles|
|US20070246902 *||Jun 21, 2007||Oct 25, 2007||Hadley Products||Vehicle leveling system|
|US20070267840 *||Sep 1, 2005||Nov 22, 2007||Sandbulte Arlin G||Air suspension system for a vehicle|
|US20070273072 *||Apr 5, 2007||Nov 29, 2007||Simard Suspensions Inc.||Tandem suspension for steerable axles|
|US20080021611 *||Jul 23, 2007||Jan 24, 2008||Hiebert Grant W||Method and apparatus for controlling ride height and leveling of a vehicle having air suspension|
|US20080111337 *||Nov 8, 2007||May 15, 2008||Aisin Seiki Kabushiki Kaisha||Vehicle height adjusting apparatus|
|US20080238017 *||Jun 6, 2008||Oct 2, 2008||Arlin Gene Sandbulte||Air suspense system for a vehicle|
|US20090127531 *||Nov 15, 2007||May 21, 2009||Nikesh Bakshi||Medical Imaging Leveling|
|US20100030425 *||Oct 8, 2009||Feb 4, 2010||Firestone Industrial Products Company, Llc||Method and system for aligning a vehicle with an artificial horizon|
|US20110042908 *||Apr 30, 2008||Feb 24, 2011||Bombardier Recreational Products Inc.||Adjustable height suspension system|
|US20120046830 *||Mar 29, 2010||Feb 23, 2012||Gerhard Hojak||Method for Controlling a Pneumatic Spring Assembly of a Motor Vehicle|
|US20130046440 *||Aug 14, 2012||Feb 21, 2013||Dr. Ing. H.C. F. Porsche Aktiengesellschaft||Control unit of a ride level control system, and ride level control system|
|CN101244685B||Jan 24, 2008||Jun 9, 2010||一汽解放青岛汽车厂||Electric control device of air chamber for air suspension follow-up bridge and control method|
|U.S. Classification||280/6.153, 701/37, 280/5.514, 280/5.515, 280/124.16, 280/6.157|
|International Classification||B60G17/052, B60G17/056, B60G17/015|
|Cooperative Classification||B60G17/0523, B60G2800/012, B60G2400/1062, B60G2400/0512, B60G2800/912, B60G17/0155, B60G2500/302, B60G2500/204, B60G2600/02, B60G2800/702, B60G2400/0511, B60G2400/252, B60G2600/82, B60G2600/20, B60G2500/203, B60G2400/1042, B60G2800/014|
|European Classification||B60G17/052V, B60G17/015B1|
|Mar 1, 2005||AS||Assignment|
Owner name: VALID MANUFACTURING LTD., CANADA
Free format text: ASSIGNMENT OF ASSIGNORS INTEREST;ASSIGNORS:HIEBERT, GRANT W.;FENKHUBER, JACK W.;CLANCY, GERALD W.;REEL/FRAME:015808/0569
Effective date: 20050114
|Nov 30, 2009||FPAY||Fee payment|
Year of fee payment: 4
|Nov 4, 2013||FPAY||Fee payment|
Year of fee payment: 8